Fig. 9
From: Observation of reflectionless absorption due to spatial Kramers–Kronig profile
Reflection of a linear profile slab. a The linear permittivity profile slab with the same thickness and variation range of the imaginary part of permittivity as those shown in Fig. 8b. The real part of the linear permittivity profile is set as a constant value of 1, so that it can perfectly match the real part of the permittivity of air. The imaginary part is linearly increased from 0 (at the front edge located at x = 5.45λ 0) to the maximum value of 6.7 at x = 12λ 0. Here both the maximum value and its location are the same as those in Fig. 8b. It is then linearly decreased from 6.7 to 0 at the back edge of the slab located at x = 13.45λ 0. This configuration is the best case for an absorbing slab with a linear permittivity profile to obtain an optimal reflection performance. b The simulated wave reflection due to the linear profile slab
